Departamento de Física - FFCLRP- Universidade de São Paulo, Ribeirão Preto, SP 14040-901, Brazil.
Nanotechnology. 2023 Jun 1;34(33). doi: 10.1088/1361-6528/acd387.
A radiolytic synthesis of silver nanoparticles was carried out in combination with a microfluidic method to produce liquid radiation detectors. The detector response was analyzed by correlating the absorbed dose with the dispersion's absorbance and with the hydrodynamic radius (HR). Samples were irradiated with x-rays of varying beam energies and dose rates and the data were discussed to elucidate how nucleation and growth processes are affected by the radiation quantities. Results reveal that HR does not change with the absorbed dose, but can be well controlled by varying the precursors concentration, beam energy, and dose rate. Increased precursor concentrations or dose rates favor nucleation, leading to the formation of smaller HR particles and increased detector sensitivity. Upon increasing the x-ray energy, growth is favored, leading to larger HR and decreased detector sensitivity. It is shown that HR and detector sensitivity are strongly correlated so that HR dictates detection sensitivity: the smaller the HR, the higher the sensitivity. Therefore, the dependence of the HR on the dose rate and on the x-ray energy establishes a new method for the controlled growth of colloidal silver, besides opening new possibilities for ionizing radiation detection.
采用放射化学合成法与微流控法相结合，制备了用于液体辐射探测器的银纳米粒子。通过将吸收剂量与分散体的吸光度和水动力半径（HR）相关联，分析了探测器的响应。用不同能谱的 X 射线对样品进行辐照，并讨论了数据，以阐明成核和生长过程如何受到辐射量的影响。结果表明，HR 不随吸收剂量而变化，但可以通过改变前体浓度、射线能量和剂量率来很好地控制。增加前体浓度或剂量率有利于成核，导致 HR 更小的粒子形成和探测器灵敏度的增加。随着 X 射线能量的增加，生长变得有利，导致 HR 增大和探测器灵敏度降低。结果表明，HR 和探测器灵敏度具有很强的相关性，因此 HR 决定了检测灵敏度：HR 越小，灵敏度越高。因此，HR 对剂量率和 X 射线能量的依赖性为胶体银的控制生长建立了一种新方法，同时为离子辐射探测开辟了新的可能性。
